ASTRONOMY CLUB OF TULSA

November 2000

Friday, November 10, 2000 at 6:00 PM

Where

Furr's Cafeteria

Northwest corner 41st & Garnett

John Land

Friday Nov 10 is our annual club dinner at Furr's cafeteria. Many of our members look forward to this annual time to visit together in a relaxed atmosphere. The plan is to arrive about 6:00 PM and go through the line to choose from Furr's excellent choices of foods. We have a room reserved so that we can eat and visit. We need to pay for our food early so that we do not delay the Furr's staff waiting on us. We will have a brief business meeting for our annual reports and officers’ elections. Gary Bushmaster and others will be sharing about their recent trip to the Okie Tex Star party in the Oklahoma Panhandle. We will also be sharing information about future club events. We need to conclude our meeting by 8:00 PM so that the room can be cleaned before closing time at 8:30 PM.

Club Officer Elections: At our October meeting we were not able to complete our officer’s elections due to a small turn out. We will complete elections at the Nov. 10 meeting. The candidates who have volunteered run for Office are: President - John Land; Vice Pres - Dennis Mishler; Secretary - Teresa Kincannon; Treasurer - Nick Pottorf with Richie Shroff serving as associate treasurer. Board Candidates are Gerry Andries, Aaron Coyner and Steve Chapman.  Nominations from the floor are also open at the time of the meeting. We have a number of other volunteer positions and are looking for members who are dedicated to the future of the Astronomy Club of Tulsa and willing to contribute their time and energies to promoting the club and its activities. You don’t have to know a lot about astronomy but do have to be willing to share your enthusiasm for learning more about this marvelous universe and sharing it with others. If you are that person, then please contact one of the officers or board members about your desire to serve.

Friday Dec 15 Meeting at TU. We have invited Robert Daniels, of Silver Wings Art studio in Oklahoma City to come demonstrate his Art of the Universe collection. At the meeting he will let us observe as he completes an actual painting, which will be donated to the club after the meeting. He will also have some of his collection available for sale, which may help you with those special Christmas gifts for the astronomer. Several people have seen his demonstration of talent and say it is well worth the time. You won't want to miss this one!

Time to pay your Club DUES. Memberships are $25 per year regular or $15 per year student. You must be actively enrolled in High School or College to qualify for student rate. As a member you will continue to receive our club newsletter and opportunities to participate with us in our activities. You will also receive a free subscription to the Astronomical League's Reflector newsletter and discounts on League materials. Discounts are also available for subscriptions to the two leading Astronomy periodicals. Sky and Telescope is $30 /yr and Astronomy magazine is $29. Don't miss out on the great stories for 2001.  Send your checks to our treasure Nick Pottorf at 3832 S Victor, Tulsa OK 74105.

Astronomy club Shirts: Aaron Coyner has designed some nice looking astronomy club shirts with our club logo and name embroidered on the front. They are short-sleeved Polo Type collared shirts in a 60/40 blend. He is taking orders for them at $17.00 each.  Contact him at 918.259.8757.   

On Christmas Day 2000 there will be a 40% partial solar eclipse visible from Tulsa and almost all of the USA and Canada. We will be selling Collector Edition Eclipse viewing glasses for only $1.00 each. You may pick up some to help us sell at our club meeting. We have ordered 1000 pair. Each pair of glasses comes with information about the eclipse and safety instructions.

The eclipse glasses will make a great stocking stuffer and provide a family activity after all the presents on Christmas morning. Contact schools and youth groups in your area of town and let them know they are available. You'll be amazed how quickly they sell.

You may order them by mail by sending a: STAMPED SELF ADDRESSED LEGAL SIZED envelope and $1.00 for EACH PAIR of glasses you wish to purchase to: Astronomy Club,  25209 E. 62nd St,  Broken Arrow, OK 74014

NOTE: Up to THREE pair of glasses will fit in an envelope.  If you want more than three pair, include an extra stamped and addressed envelope for multiples of three.

For large quantities contact us at our number or email.  Leave details how to contact you via email or phone day or evening.

Our Phone is 688 - MARS or email < John Land e-mail >

9:38 AM Begin Altitude 19 deg Azimuth 140 deg	11:00 AM Maximum Altitude 27 deg Azimuth 158 deg	12:30 PM End Altitude 30 deg Azimuth 182 deg

John Land has Baader Solar Filter material available for you to make your own filters. 4-inch squares are $3, and 5-inch squares are $5 each. Larger sizes available by request.

We are getting lots of calls for groups to visit the observatory or for us to come to schools with our telescopes. Most of these groups make generous donations toward the expenses of our observatory. We especially need help in November. Please contact Gerry Andries and confirm your commitment to help with these events.  Contact - Gerry Andries - Phone or < Gerry Andries e-mail >

The following is the current schedule of star parties and public groups.  All events are at the RMCC unless noted otherwise:

DAVID'S ASTRO CORNER

"LEONIDS OR MOONIDS - Part 2"

 By David Stine

We are only a week away from what could be an awesome meteor display or just an ordinary one.  Either way the excitement is building.  The earth will be passing through 3 separate Leonid meteor streams within a 26 hr period beginning the morning of November 17th at 1:50a.m. CDT and climaxing on the morning of November 18th at 4:01a.m.  CDT.  In last months article you can find details of this event.  Please note that there is one time mistake.  It should say the 1932 stream is passed through by Earth at 1:50a.m. the morning of the 17th not the 16th.  Just a brief reminder of the important times you need to be aware of:

1. 1932 stream, Earth passes near at 1:50a.m.  Nov. 17th
2. 1733 stream, Earth passes through at 9:44p.m.  Nov. 17th
3. 1866 stream, Earth passes through at 1:51a.m.  Nov. 18th (This is the peak we are going to be the most interested in.)

As I said in last months article the moon will be a problem, but then again it could be an asset.  The moon will pass closer to the 1932 trial than the earth an possibly provide alot of Leonid activity on the surface.  When a meteor hits the moon its like a spark or flash that we see anywhere on the dark area of the moon.  People like myself and KC Lobrecht witnessed this last year during the Leonids.  The problem this year is that they will be hitting the other side of the moon that is not visible to the earth.  However, we may be able to see indirectly the results as when a meteor hits the moon it vaporizes dust and rock.  According to Jody Wilson of the Boston Imaging Science Team, some of the vapors will contain sodium which scatters sunlight.  If any of the impact vapors drift over the limb we might be able to see this as a glow like a faint low-pressure sodium lamp.  This could provide for some interesting views if here on earth the Leonids don't pan out.  Next year will even be a better year for spotting Leonid impacts on the moon as it will be a slim crescent and David Asher and Rob McNight predict as many as 10,000 meteors per hr bombarding the moon.  It will look like flash bulbs going off on the moon.  This year we will have to hope for ghostly vapors on the moons limb to reveal any impacts.

Asteroid 4179 Toutatis passed earth less than 29 Lunar distances from earth on Halloween night.  This asteroid is one of the PHA's or Potentially Hazard Asteroids.  This was close for an asteroid but wait until 2004.  This asteroid will pass only 4 lunar distances from earth on September 29, 2004.  This will be the closest for any asteroid for the next 30 years.  It will easily be picked up by binoculars.  Mark the date down in your calendar.

Thats it for this month in my astro corner, don't forget the two nights of Leonid Meteor Observing at the RMCC Observatory Nov. 16-17 and the morning of the 17th and 18th.  Hope to see you there.

November SKY FORUM

By Don Cole

I hope this months article reads good and makes sense, as I am having to literally throw it in a pot and stir it up.

Pulsars and Neutron Stars

A number of distinct sources of radio pulses, referred to as pulsars, have been discovered with radio telescopes. Typical pulsation periods of the pulsars are near 1 sec. The periods range from several seconds to a tiny fraction of a second, as confirmed by optical and X-ray observations. The pulsation periods are so constant that only the most precise clocks can detect a slight increase in the average pulse interval for several pulsars; this increase indicates that it would take approximately 1 million years for typical periods to double.

The evidence strongly suggests that pulsars are rotating neutron stars with diameters of perhaps only about 16 km (about 10 mi). Probably they rotate once per pulsation period. Their density is so enormous that if the volume of the ball on a ballpoint pen were packed with neutrons, as in a pulsar, it would contain more than 91,000 metric tons of mass.

Evolution of Stars

The formation and development of stars have been the subject of many hypotheses and conjectures by scientists. Theories of stellar evolution are based primarily on clues obtained from studies of the stellar spectra related to luminosity. Observation has shown that many known stars can be combined in a regular sequence in which the brightest stars are the hottest and the smallest stars are the coolest and faintest. This series of stars is known as the main sequence on the temperature-luminosity diagram developed from the work of the Dutch astronomer Ejnar Hertzsprung and the American astronomer Henry Norris Russell and known as the Hertzsprung-Russell diagram. Two exceptions to this grouping are the so-called red giants and white dwarfs. The red giants are bright stars of comparatively large dimensions; white dwarfs are low in brightness, small, and extremely dense.

A star begins its life as a large and comparatively cool mass of gas. The contraction of this gas and the subsequent rise of temperature continue until the interior temperature of the star reaches a value of about 1,000,000 degrees C (about 1,800,000 degrees F). At this point a nuclear reaction takes place in which the nuclei of hydrogen atoms combine with heavy hydrogen deuterons (nuclei of so- called heavy hydrogen atoms) to form the nucleus of the inert gas helium. The latter reaction liberates large amounts of nuclear energy, and the further contraction of the star probably is halted.

When the release of energy from the deuteron-hydrogen nucleus reaction ends, contraction begins anew, and the temperature of the star increases again until it reaches a point at which a nuclear reaction can occur between hydrogen and lithium and other light metals present in the body of the star. Again energy is released and contraction stops. When the lithium and other light materials are consumed, contraction resumes, and the star enters the final stage of development in which hydrogen is transformed into helium at extremely high temperatures through the catalytic action of carbon and nitrogen. This thermonuclear reaction is characteristic of the main sequence of stars mentioned above and continues until all the available hydrogen is consumed. The star gradually swells and becomes a red giant. It attains its greatest size when all its central hydrogen has been converted into helium. If it is to continue shining, its temperature at the center must rise high enough to cause fusion of the helium nuclei. During this process the star probably becomes much smaller and denser. When it has exhausted all possible sources of nuclear energy, it may contract further and become a white dwarf. This final stage may be marked by the stellar explosions known as novas. When a star sheds its outer envelope explosively as a nova or supernova, it returns to the interstellar medium elements heavier than hydrogen that it has synthesized in its interior. Future generations of stars formed from this material will therefore start life with a richer supply of heavier elements than the earlier generations of stars. Stars that shed their outer layers in a nonexplosive fashion become planetary nebulas, or old stars surrounded by spheres of radiating gases.

Massive stars, many times the mass of the sun, run through their cycle of evolution rapidly in astronomical time, perhaps only a few million years from birth to a supernova-type disruption. The remainder may then become a neutron star. A limit exists for the size of neutron stars, however, beyond which such stars are gravitationally bound to keep contracting until they become a black hole, from which light radiation cannot escape. Typical stars such as the sun may persist for many billion of years. The final fate of low-mass dwarfs is unknown, except that they cease to radiate appreciably. Most likely they become burned-out cinders, or black dwarfs.

The birth of stars is intimately connected with the presence of dust grains and molecules, as in the Orion nebula region of earth's galaxy. Here, molecular hydrogen (H2) is compressed to high densities and temperatures, dissociating the molecules. The atomic hydrogen then recollapses and forms a dense stellar core that gravitationally attracts surrounding material. The hot core dispels the cocoon of the overlying molecules, and the new star emerges. Further gravitational heating raises the temperature until nuclear processes can occur. Stars are generally born in small groups at one edge of a large molecular cloud. Successive generations of stars eat into the edge of the cloud more and more, leaving a trail of stars of increasing ages.

The birth of stars has been observed in photographs taken of a sky region over a period of years. Modern techniques of space-based ultraviolet, infrared, and radio astronomy have further pinpointed sites of star formation and actual processes taking place.

*** Astronomy Dictionary ***

After reading the following paragraph you might want to skip to the bottom of this discussion and read the last line, it should bring things into clearer focus for most of us.

Magnitude : is used to designate the apparent brightness of a star as viewed from the earth. The ancient Alexandrian astronomer Ptolemy originally divided all visible stars into six magnitudes: the brightest were called first magnitude, those barely visible to the naked eye were called sixth magnitude, and the other visible stars were assigned intermediate positions. After the introduction of the telescope in the 17th century, this system of magnitudes was used and extended to the fainter stars in different ways by different astronomers. In the 19th century a standard system was finally adopted under which a star of any given magnitude is 2.512 times as bright as a star of the next higher magnitude; thus, for example, a star of the second magnitude is 2.512 times as bright as a star of the third magnitude. The advantage of this particular magnitude ratio, 2.512, is that it coincides closely with the Ptolemaic system; and because 2.512 is the fifth root of 100, a star of the first magnitude is exactly 100 times as bright as a star of the sixth magnitude, a star of the sixth magnitude is exactly 100 times as bright as a star of the 11th magnitude, and so on. The mean of the magnitudes of several hundred stars found in the Bonn Durchmusterung catalog, which was prepared by the German astronomer Friedrich Wilhelm August Argelander about 1860, was taken as the standard of the scale for calibration purposes.

With accurate instruments, such as bolometers and radiometers, astronomers today can measure differences as small as one-hundredth of a magnitude. Stars with magnitudes between 1.5 and 2.5 are called second-magnitude stars. Stars brighter than magnitude 1.5, of which there are 20, are called first-magnitude stars. Thus, the first-magnitude star Aldebaran has an actual magnitude of 1.1; the slightly brighter first-magnitude star Altair has a magnitude of 0.9. The brightest stars are brighter than magnitude zero. Sirius, the brightest star outside the solar system, has a magnitude of -1.6. The sun has a magnitude of -26.7, inasmuch as it is about 10 billion times as bright as Sirius in the earth's sky.

Because the eye is more sensitive to yellow light than to blue light, whereas ordinary photographic film is more sensitive to blue than to yellow, the visual magnitude of a star may differ from its photographic magnitude. A star of visual magnitude 2 may have photographic magnitude 1 if blue, or it may have photographic magnitude 3 if yellow or red. The faintest star that can be observed by long photographic exposure with the largest telescope is of the 23d magnitude.

For stars brighter than approximately tenth magnitude, the number of stars of each magnitude is about three times as great as the number of stars of the next higher magnitude. Thus there are 20 first-magnitude stars, about 60 second-magnitude stars, and about 180 third-magnitude stars. This ratio becomes less than 3 to 1 for the fainter stars, being approximately 2 to 1 for stars of the 20th magnitude.

Absolute magnitude, as opposed to apparent magnitude, indicates the brightness that a star would have if it were placed at a distance from the earth of ten parsecs, or 32.6 light-years. By rating stars in this way, astronomers are able to compare them with respect to intrinsic brightness. The sun, for example, has an absolute magnitude of +4.7.

Doppler Effect : In physics, the apparent variation in frequency of any emitted wave, such as a wave of light or sound, as the source of the wave approaches or moves away, relative to an observer. The effect takes its name from the Austrian physicist Christian Johann Doppler, who first stated the physical principle in 1842. Doppler's principle explains why, if a source of sound of a constant pitch is moving toward an observer, the sound seems higher in pitch, whereas if the source is moving away it seems lower. This change in pitch can be heard by an observer listening to the whistle of an express train from a station platform or another train. The lines in the spectrum of a luminous body such as a star are similarly shifted toward the violet if the distance between the star and the earth is decreasing and toward the red if the distance is increasing. By measuring this shift, the relative motion of the earth and the star can be calculated.

After having said all that, let's just say some stars are brighter than others OK?

So until next month Dark Skies and Steady Seeing to You...

FOR SALE

Celestron 14" optical tube assembly with Lumicon Giant variable focal reducer/camera adaptor/guider and Tuthill 14" solar filter plus 5.5" unobstructed off axis adaptor, f-28(for planetary, double star or h-alpha).

Byers 812 German Equatorial mount on 5 foot portable pier.Fork mount for up to 16" diameter tube. Swings 30", could hold maybe 1000 pound package, driven by 12" Mathis gear. Observatory jewel. I had a 14 1/4" f-6 Newtonian plus several accessories in it. Would hold a C14 like a ROCK.

Contact George Allen,  geonjod@earthlink.net

Astronomy Club of Tulsa, 918.688.MARS

President: John Land

Vice President: Grant Cole

Secretary: Teresa Kincannon

Treasurer: Nick Pottorf

RMCC Observatory Manager: Gerry Andries

Observing Chairman: David Stine

Web Master: Dean Salman

New Membership: Dennis Mishler

Librarian: Ed Reinhart

Education Coordinator: Scott Parker